An intelligent pen to assess anxiety levels through pressure sensors and fuzzy logic

Anxiety is a physiological state of activation, which is commonly measured using direct or indirect methods. In psychology, the tools used to obtain information about the state of anxiety in a subject are commonly, self-reports, which represent how the person perceives his or her own physiological and cognitive state of anxiety. Additionally, anxiety has been tested on graphics tests, which evaluate the characteristics of strokes, such as the pressure exerted by the pen or the oscillation of the line. These characteristics are measured in an indirect and, in certain way, subjective manner; thus it is necessary to develop objective tools that throw specific and directly measurable data. For these reasons in this paper, we present an intelligent pen that has the objective of providing a presumptive diagnosis of anxiety levels that presents a person (especially students of middle and higher education). The pen uses an electronic device to measure two pressure levels (at pen tip and pen body) and an inference system based on fuzzy logic. This prototype has been tested with 9 volunteers in an experiment consisting in two stages: a first under simulated stress condition, and a second under normal writing.